1. Field of the Invention
The present invention generally pertains to retaining walls, and more particularly to two-stage mechanically-stabilized retaining earth walls and related methods wherein the first stage entails construction of an earth wall using weld-wire components in a known manner and the second stage entails attachment of pre-cast concrete panels through the use of a substantially horizontal connector in accordance with the present invention.
2. Description of the Related Art
It is known within a variety of fields to construct retaining walls for various purposes. Within the road construction industry, for example, it is known to erect temporary and permanent retaining walls for embankments, roadway supports, bridge abutments and the like. It is also known that these retaining walls can be constructed using a variety of techniques and materials, including, for example, concrete and/or welded wire components. An example of a precast modular wall panel is disclosed in U.S. Pat. No. 5,259,704 to Ogorchock. Examples of retaining walls constructed using welded wire components may be found in a number of U.S. patents, including, for example, U.S. Pat. No. 4,117,686 to Hilfiker, U.S. Pat. No. 4,329,089 to Hilfiker et al., U.S. Pat. No. 4,391,557 to Hilfiker et al., U.S. Pat. No. 4,505,621 to Hilfiker et al., U.S. Pat. No. 4,856,939 to Hilfiker, and U.S. Pat. No. 5,722,799 to Hilfiker.
The concept of a two-stage retaining wall is also known within the road construction industry. As mentioned above, two-stage retaining wall systems include a welded wire earth wall as the first stage and a precast concrete wall made from precast concrete panels as the second stage. Examples of such a two-stage wall system may be found in Performance of Mechanically Stabilized Earth walls over compressible soils, R. A. Bloomfield, A. F. Soliman and A. Abraham, The Reinforced Earth Company, Vienna, Va., USA, and also in U.S. Pat. No. 5,971,669 to Crigler. A serious drawback to the prior art, however, relates to the design and method by which the precast concrete panels are connected to the welded wire earth wall. More specifically, with respect to the Crigler '669 patent for example, once the welded wire wall is in place, and the precast concrete panels are individually positioned for connection to the welded wire wall, the workers use a connector assembly to connect the precast concrete panels to the welded wire wall. One of the big problems with the Crigler '669 design is that the connection point on the precast concrete panel is not at the same height as the corresponding connection point on the welded wire wall. As a result, the connector assemblies must be installed at an inclined angle as opposed to in the horizontal plane. This represents a serious design flaw as it fails to address the fact that the welded wire wall will continue to settle after the precast concrete panels are attached to the welded wire wall. As a result, when the welded wire wall settles, it will lower the end of the connector assembly that is spaced away from the precast concrete wall, thereby either pulling the precast concrete ball towards the welded wire wall or pushing it away from the welded wire wall, depending on whether the connector assembly is installed to be upwardly or downwardly inclined towards the precast concrete wall. For example, the connector assembly is shown in a downwardly installed configuration in FIG. 4c of the Crigler '669 patent.
As will become apparent from the following description and discussion, however, the present invention, which is also directed to two-stage retaining walls, provides an improved design that enables on-the-fly installation of a connector in a horizontal plane to thereby minimize the effect of later settling of the welded wire wall. In this manner, the various embodiments of the two-stage retaining walls and related systems and methods of the present invention overcome the deficiencies of the prior art and constitutes an improved and more cost-effective retaining wall in comparison to the walls and methods disclosed in the above-listed disclosures.